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CSS SQL Server Engineers

This is the official team Web Log for Microsoft Customer Service and Support (CSS) SQL Support. Posts are provided by the CSS SQL Escalation Services
  • Blog Post: Every time I ‘ATTACH DATABASE’ SQL logs error 1314 for SetFileIoOverlappedRange

    Turns out this is an issue in the SQL Server code and the error is a bit noisy during attach database. When opening the database files, SQL Server calls SetFileIoOverlappedRange (when enabled properly) in order to help improve I/O performance.  This is commonly done under the SQL Server, service...
  • Blog Post: SQL Server–Storage Spaces/VHDx and 4K Sector Size

    This blog outlines a new twist to my previous blog outlining issues with 4K sector sizes. SQL Server - New Drives Use 4K Sector Size: http://blogs.msdn.com/b/psssql/archive/2011/01/13/sql-server-new-drives-use-4k-sector-size.aspx In the previous post I discussed that it was unsafe for the I/O subsystem...
  • Blog Post: SQLIOSim Checksum Validations

    I had a very specific question asked of me related to the SQLIOSIM.exe, checksum validation logic.  It is pretty simple logic (on purpose) but effective so here are the basics. The key is that there are multiple memory locations used to hold the data and do the comparison.   1.     ...
  • Blog Post: Don’t change value of that parameter

    Parameter sniffing is a well known among SQL User community.   But I have seen variations of this frequently that need a bit creative handling and solution may not that straight forward. One of the variation is that a user changes the value of the parameter inside the procedure.  When...
  • Blog Post: How It Works: CMemThread and Debugging Them

    The wait type of CMemThread shows up in outputs such as sys.dm_exec_requests.  This post is intended to explain what a CMemThread is and what you might be able to do to avoid the waits.  The easiest way to describe a CMemThread is to talk about a standard Heap, HeapCreate and the options (with...
  • Blog Post: SQLCLR and sp_OA* procedures are not compatible

    We ran into an issue today that is a bug you may need to be aware of because of its behavior.   When a SQLCLR procedure calls back into the SQL Server (in proc provider) and executes sp_OA*, during the callback activity, it triggers a bug (currently filed and being evaluated) that results in...
  • Blog Post: How It Works: SQL Server 32 bit PAE/AWE on (SQL 2005, 2008, and 2008 R2) – Not Using As Much RAM As Expected!

    This issue was puzzling until we stepped through the code and studied it in some detail.   The report was “SQL Server won’t use the physical memory I expect it to use.” Scenario:   SQL Server 2008 R2, 32GB RAM  - SQL only using ~22GB of total memory and won’t use anymore. Let me try...
  • Blog Post: How Can Reference Counting Be A Leading Memory Scribbler Cause?

    The concept of the memory scribbler comes up quite a bit in support.   The term can often be over used but I ran into a specific example that commonly fools people, including support engineers.  The random nature and even the resulting behaviors are so broad that these issues often take...
  • Blog Post: SQL Server: Clarifying The NUMA Configuration Information

    The increased number of cores per socket is driving NUMA designs and in SQL Server support we are seeing more NUMA machines and less pure SMP machines.    For whatever reason over the past 2 weeks I have fielded a bunch of questions around NUMA and the information is good for everyone...
  • Blog Post: Secondary Access to File Stream(s) File, In Open Transaction, May Hang

    This post is directly from an issue I have been working on.  The behavior is very difficult to simulate because of the flags and timings involved.   In this post I will attempt to describe the scenario and provide you with a simple workaround for your applications. Reproduction Steps 1...
  • Blog Post: SQL Server - New Drives Use 4K Sector Size

    In a lengthy discussion this past week I was reminded that Jan 2011 is when the hard drive manufactures agreed to focus on drives with sector sizes of 4K. I have read all the latest materials about this over the past week and you can too. Just search for 512e or Advanced Format Sector sizes and you will...
  • Blog Post: Error 17953 - SidePageTable::Init() DeviceIoControl() : Operating system error 1(Incorrect function.) encountered.

    When attempting to run dbcc checkdb or create a snapshot database you may encounter the following errors when using a UNC location that does not support all sparse file operations. 2010-09-21 17:27:26.47 spid82 Error: 17053, Severity: 16, State: 1. 2010-09-21 17:27:26.47 spid82 SidePageTable::Init()...
  • Blog Post: How It Works: Timer Outputs in SQL Server 2008 R2 - Invariant TSC

    I would love nothing more than to take you back to my high-school days running the 440 yard hurdles (yes yards not meters) where timing was done with a stop watch (you know the old, moving dial style) but timers on the PC don't allow that simplicity. I have discussed the timing behavior is SQL Server...
  • Blog Post: Why is my SQL Clustered Instance changing authentication modes?

    We get our fair share of cases related to SQL Server running ( or not running) on a Windows Cluster.  I had one of them recently where the customer was seeing different authentication modes for SQL Server depending on which node of the 2-node cluster that it was online on. The Errorlogs document...
  • Blog Post: AWE Allocated Values Reported Incorrectly (Large or Negative Value)

    I ran into an issue today that is documented but you have to know where to find it so I wanted to point it out. In the middle of a lengthy KB article # 907877 ( http://support.microsoft.com/kb/907877 ) the the following comment. "In a NUMA-enabled system, this value can be incorrect or negative...
  • Blog Post: Reporting Services and the MS09-062 GDR (GDI+)

    Updated 10/29/09:  Added section describing SQL Engine only servers at the bottom.   Brian Hartman did a great job outlining what the GDR is and why we had it.  You can read it here .  I’m not going to rehash that here.  What I wanted to do is outline some of the scenarios involving...
  • Blog Post: How It Works: What are the RING_BUFFER_RESOURCE_MONITOR telling me?

    The ring buffer records (which can be sent to XEvent) for Resource Monitor and Memory Broker are the key aspects to understanding RM.  The record is produced when a change is detected in state monitored by RM.    CREATE EVENT SESSION RingBufferInfo ON SERVER     ADD EVENT...
  • Blog Post: SSIS 2005 and the .NET Garbage Collector

    I was troubleshooting an SSIS Out of Memory issue the other day which led us into how the .NET Garbage Collector (GC) works.  When debugging it, I found that we were using the Workstation GC with Concurrent GC On (this is the default for .NET applications).  The following blog discusses the...
  • Blog Post: Troubleshooting sp_xp_cmdshell_proxy_account Errors

    I was attempting to establish the command shell proxy on my local machine and ran into a series of errors.   As I looked at them more I decided to file some work items with the SQL dev team to provide better context in the message text.   I hope this post will help provide some insight...
  • Blog Post: Reporting Services Windows Service will not start after applying MS08-052

    We have been seeing a few cases where the Windows Service for Reporting Services will not start after applying the following fix: MS08-052: Description of the security update for GDI+ for SQL Server 2005 Service Pack 2 GDR: September 9, 2008 http://support.microsoft.com/kb/954606/ You...
  • Blog Post: SQL Server 2005 - RDTSC Truths and Myths Discussed

    I posted some updates to my blog entry about the RDTSC and drift warnings in May. See the following link http://blogs.msdn.com/psssql/archive/2006/11/27/sql-server-2005-sp2-will-introduce-new-messages-to-the-error-log-related-to-timing-activities.aspx Because the CPU drift issue has continued to generate...
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